§ 301. Conveyance and record as evidence. 1. The certificate of the acknowledgment or of the proof of a conveyance, or the record, or the transcript of the record, of such a conveyance, is not conclusive, and it may be rebutted, and the effect thereof may be contested, by a party affected thereby.

2. If it appears that the acknowledgment or proof was taken upon the oath of an interested or incompetent witness, the conveyance, or the record or transcript of the record thereof, shall not be received in evidence until its execution is established by other competent proof, except in a case where the title to the land conveyed or affected by such conveyance or instrument has passed to a subsequent purchaser for a valuable consideration.